1. Field of the Invention
The present invention relates to a one-reel typed tape cartridge used for a magnetic recording and reproducing apparatus and a method of producing the same.
2. Description of the Prior Art
A one-reel typed tape cartridge used for a magnetic recording and reproducing allows an opening portion of a case to be opened and closed using a door member in order to pull out and encase the tape. Conventional arts as to such a door member will be explained, referring to FIG. 6 and FIG. 7.
In the conventional art in FIG. 6, a door member 130 which opens and closes an opening 160 of a tape cartridge is biased in a direction designated by an arrow of the drawing using a torsion-coil typed spring member 200 so as to always close the opening 160. At the door member 130, an elongate spring-hook-opening 150 is formed in a vertical direction on the drawing being normal to the biasing direction so that a stopper 260 of a spring arm 240 at one end of the spring member 200 is engaged with the door member 130. After the stopper 260 of the spring member 200 is inserted into the elongate spring-hook-opening 150 of the door member 130, the door member 130 is slidably incorporated into a thin and elongate recess 170 extended in a longitudinal direction of the door member 130 from the opening portion 160 (refer to Japanese Laid-open application No. 11-328922).
Further, in another conventional art in FIG. 7, a door member 100 which opens and closes an opening of a tape cartridge (like the opening shown in FIG. 6) is biased using a spring member 110 in a direction designated by an arrow in the drawing so as to always close the opening. An inserting opening 102 is formed in a vertical direction of the drawing at a connecting portion 101 of one end portion of the door member. A curved portion 112 is formed at a tip part of the spring member 110. The spring member 110 is inserted into the inserting opening 102 of the door member 100 from its end portion 111 from below in the drawing, and then the curved portion 112 is positioned within the inserting opening 102. Thus, after the spring member 110 is hooked to the connecting portion 101 to establish a temporal assembling state, the door member 100 is incorporated into the cartridge case.
However, in the conventional example of FIG. 6, when the spring member 200 and the door member 130 lie in the temporal assembling state, it becomes difficult to hold the temporal assembling state. Therefore, the temporal assembling operation needs to be completed just before incorporating them into the cartridge case, so that the working becomes complicated and the assembling performance becomes worse. If the length of the stopper 260 at the tip part of the spring arm 240 of the spring member 200 becomes longer owing to faulty to be occurred upon bending it, when the door member 130 is slid within the recess 170 for opening and closing the door member 130, the stopper 260 will be contacted with an inner wall 171 of the recess, resulting that sliding defect of the door 130 occurs and further the inner wall 171 is injured with scratching.
Further, in the conventional example of FIG. 7, in the assembling operation that the spring member 110 is inserted from the end portion 111 into the inserting opening 102 of the door member 100, the spring member 110 is thin and further a tip part thereof has the curved portion 112 and the inserting opening 102 is also relatively small, resulting in that the assembling performance becomes worse and this operation cannot be automated i.e. must be performed by a hand. Therefore, more producing cost will be required. Additionally, the inserting opening 102 is relatively large under the temporal assembling state between the spring member 110 and the door member 100, so that the end portion 111 is sometimes unexpectedly released from the inserting opening 102, depending on its handling manner. Then the operation needs to be again performed, resulting in causing non-efficiency.